GABERONE, Dec 8 (Reuters) - Botswana has not seen a rise in COVID-19 hospitalisations despite being one of the first countries to detect the Omicron variant, and has managed to fully vaccinate 71% of its 1.3 million eligible population, the health minister said on Wednesday. The heavily mutated variant has caused alarm among scientists and governments and is widely expected to become dominant because of its high transmissibility. It has spread to at least 57 countries. read more "Currently we only have one person in ICU (intensive care). But there is a trend that we have noticed which is that those that get seriously ill have not been vaccinated," Health Minister Edwin Dikoloti told a news conference. The World Health Organization said in its weekly epidemiological report on Wednesday that more data was needed to assess the severity of disease caused by the Omicron variant and whether its mutations might reduce protection from vaccine-derived immunity.The number of reported COVID-19 cases in South Africa doubled in the week to Dec. 5 to more than 62,000 and "very large" increases in incidence have been seen in Eswatini, Zimbabwe, Mozambique, Namibia and Lesotho. The Omicron variant can partially evade the protection from two doses of the vaccine produced by Pfizer Inc (PFE.N) and BioNTech (22UAy.DE), the research head of a laboratory at the Africa Health Research Institute in South Africa said on Tuesday, reporting the results of a small, limited study.